Datasheet

AD620
REV. D
–15–
for these currents; therefore when amplifying “floating” input
V
OUT
7
AD620
– INPUT
R
G
LOAD
TO POWER
SUPPLY
GROUND
REFERENCE
2
1
8
3
4
5
6
+ INPUT
+V
S
–V
S
Figure 40a. Ground Returns for Bias Currents with
Transformer Coupled Inputs
sources such as transformers, or ac-coupled sources, there must
be a dc path from each input to ground as shown in Figure 40.
Refer to the Instrumentation Amplifier Application Guide (free
from Analog Devices) for more information regarding in amp
applications.
V
OUT
7
AD620
– INPUT
+ INPUT
R
G
LOAD
TO POWER
SUPPLY
GROUND
REFERENCE
2
1
8
3
4
5
6
+V
S
–V
S
Figure 40b. Ground Returns for Bias Currents with
Thermocouple Inputs
100kΩ
V
OUT
7
AD620
– INPUT
+ INPUT
R
G
LOAD
TO POWER
SUPPLY
GROUND
REFERENCE
2
1
8
3
4
5
6
100kΩ –V
S
+V
S
Figure 40c. Ground Returns for Bias Currents with AC Coupled Inputs